Red Slip: Terracotta Clay Stirred into Water and Sieved

Slip is clay made liquid with water. Red slip, from red terracotta clay, coats a pot or lamp in an even red skin, joins parts of leather-hard ware, and is painted or trailed on as decoration. Soak the dry clay, stir it smooth, sieve it, and thin it until it pours like cream. The picture: a sherd of Roman red-slipped ware (St Albans District Council, CC BY-SA 4.0).